Procedural NPR Cell Shading

Hello!
Put together a first iteration of a node group that takes a (PBR) material and turns it into a cell-shaded material. It supports a main colour, flat shadows, flat highlights, and the option to add reflections/transparency to allow for mirrors/glass.
Rendered with EEVEE in blender 4.2.1.
Thumbnail:


Animation:


Node setup: